MEP/FP design for MRI suites, part one: mechanical considerations

In a two-part series, the importance of effective mechanical, electrical, plumbing, and fire protection systems design for magnetic resonance imaging suites is examined. Part one focuses on mechanical considerations.


In a two-part series, the importance of effective mechanical, electrical, plumbing, and fire protection systems design for magnetic resonance imaging suites is examined. Courtesy: Joel FilipeWithin a hospital, needs vary significantly by department and specialty treatment area. RTM Engineering Consultants understands each area's unique specifications and requirements involving mechanical, electrical, plumbing, and fire protection (MEP/FP) systems. Our expert team of engineers has designed and created engineering solutions for more than 75 health care clients and understands the complexity of this sector. 

MRI equipment is sensitive to temperature, humidity, and air pressure; therefore, mechanical systems must meet the technical requirements of the equipment while ensuring a safe and protected environment for the patients and health care staff within the facility. "Effective MEP design ensures that medical professionals can focus on their first priority-delivering high-quality patient care," said RTM Principal Tim Larson, PE.

Temperature and humidity

Proper temperature is vital for system operation, and MRI suites must have sufficient HVAC systems to regulate the temperature to the equipment vendor's recommendations. To properly regulate the computer room, supplemental cooling may be necessary depending on the limitations of the base building systems.

"Due to the complexity of these systems, it is critical to involve HVAC experts," noted Larson.

Similar to temperature, monitoring and regulating humidity is very important. Humidification or dehumidification may be necessary to keep the magnet-room and computer-room electronics within their tolerance levels based on vendor or manufacturer requirements. The HVAC system will be analyzed and tailored to meet the equipment's needs for new or existing facilities.

Emergency exhaust

MRI scanners use cryogen, usually liquid helium, to cool the magnet efficiently and reduce the power needed to operate it. Dedicated emergency exhaust systems are designed to protect an MRI suite in case of cryogen discharge. In the event of an emergency shutdown of the magnet (a quench) and the loss of superconductivity, cryogens escape quickly and pose an immediate safety risk. Cryogen leaks can result in injury, entrapment, and asphyxiation. Emergency systems activate automatically or when an alarm or sensor is turned on, and cryogen vents quickly discharge gases from the building.

Cryogen venting was an important design consideration when RTM partnered with the University of Chicago Medicine and Biological Science Division to install a new 3.0T MRI scanner in its radiology department.

"The University of Chicago MRI project required meticulous calculations to guarantee patient and staff safety," said RTM Project Manager Matt Zega, PE. "The installation involved significant building renovations, and we oversaw the process to ensure each element of the MRI suite-from shielding to emergency systems-met safety specifications."

Air change & pressurization

To reduce the amount of dust the equipment is exposed to, all spaces should have positive air pressure unless adjoining areas have different requirements. All MRI spaces need a minimum number of air changes per hour. Air-change rate (ACR) criteria should be reviewed for every facility based on adopted national, state, and local codes. 

-This article originally appeared on the RTM Engineering Consultants blog. RTM Engineering Consultants is a CFE Media content partner.

JOE , FL, United States, 03/21/17 01:00 PM:

One important element of that was missed in this series is the cooling of the magnet itself. The OEM's are very specific as far as water quality, temperatures, pressures and capacity requirements, but they fail to tell the whole story. For example, one OEM requires a chiller capable of providing 259,554 BTU, but they fail to note that the same system operating in standby mode will generate a load of 28,320 BTU!It's extremely important to enlist the assistance of a chiller manufacturer that is intimately familiar with the MRI OEM's and not simply choose a low cost chiller that meets the cooling requirements... it will be troublesome in the future. Not every chiller is capable of unloading 90% of it's capacity, and hot gas bypass costs a fortune when you consider lifetime costs.
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